... with and without a heat sink Assumptions The device and the heat sink are isothermal The thermal properties of the device and of the sink are constant The heat transfer coefficient is constant and. .. surfaces of a cylinder since heat transfer at those locations can be two-dimensional 4-2 7C Yes A plane wall whose one side is insulated is equivalent to a plane wall that is twice as thick and. .. indicates that the ball bearing can stay in the air about s before being dropped into the water 4-1 2 Chapter Transient Heat Conduction 4-2 3 A number of carbon steel balls are to be annealed by heating